1. Field of the Invention
The present invention relates to pump testing systems and more particularly pertains to a new compact and portable pump testing system for permitting testing of pumps, such as those on fire fighting equipment, at virtually any location as the portable nature of the system permits simple movement of the system and the compactness of the system permits it to be set up in almost any location, even inside of a building.
2. Description of the Prior Art
Pumps employed on fire fighting equipment, such as fire trucks, are typically periodically tested to determine if the pumps are able to perform up to design capacity for meeting various certification requirements or for simply providing piece of mind that the pumps will perform as expected when they are needed. It is desirable to conduct the periodic testing under conditions as close as possible to the conditions employed by the original certifying entities (such as Underwriters Laboratories) to determine the conformance of equipment with the various standards (such as NFPA 1901) established by standards-setting organizations (such as National Fire Protection Association (NFPA)). If these conditions are substantially duplicated, true conformance with the applicable standards and rules may be ascertained. The battery of tests may be performed approximately every year for each pumping apparatus owned by a fire fighting entity.
Sometimes such testing will be performed using a hydrant to supply the water necessary for the tests, but if the fluid cannot be recaptured it is wasted. At flow rates of 1000 gallons per minute or more, a significant amount of water can be used that can draw down the water level in a community water storage facility very quickly. It is therefore desirable to use a recirculating flow of fluid that is drawn from a reservoir and discharged back to the reservoir. In such a system, the fluid used in the test is drawn from the reservoir by an intake conduit and the fluid is then returned to the reservoir after being pumped through the pump and any testing apparatus.
While the use of a reservoir is probably the most efficient manner for testing the pumping apparatus, it is not without drawbacks that can affect the performance of the pump being tested and thus throw off the results of the testing. While the most useful reservoir is typically the most compact and portable reservoir (such as a foldable reservoir), the employment of relatively small reservoir sizes can present testing problems.
Probably the most significant problem encountered when using a relatively small, portable reservoir results from the entrainment of air bubbles in the fluid as the fluid is discharged back into the reservoir after flowing through the pump. If the air bubbles are drawn into the intake conduit and introduced into the pump, the ability of the pump to pump the fluid can be significantly degraded. Since the flow rate and velocity of the fluid discharged into the reservoir from the pump can be substantial (up to and exceeding 1000 gallons per minute per pump), the fluid can pick up a significant quantity of air before entering, or upon entering, the reservoir. Any air bubbles entrained in the fluid must be permitted to escape from the fluid before the fluid is drawn into the intake conduit. Thus, the intake of the intake conduit must be sufficiently separated from the point of the fluid reentry into the reservoir to allow this escape. Air bubbles present an even bigger problem if two pumps are being simultaneously tested. As a result, the more air that is being entrained in the fluid before reentering the reservoir, the greater the distance that needs to be maintained between the point of fluid entry into the reservoir and the point where the intake end of the intake conduit is located to allow the air bubbles to escape. The size of the reservoir may need to be increased to provide a sufficient separation between these points, and may require the use of more fluid in the reservoir so that fluid with air bubbles is not as quickly redrawn into the intake end of the intake conduit.
Another challenge resulting from the use of a relatively smaller reservoir is the inducement of movement of the fluid in the reservoir. If the fluid enters the reservoir at a relatively high velocity, then the fluid in the reservoir will be induced to move about the reservoir (such as in a swirling movement) that may make it more difficult for the pump to pull the fluid into the intake of the intake conduit, which can also negatively affect the performance of the pump being tested. Excessive induced fluid movement may also cause any air bubbles in the fluid to move more quickly toward and into the intake end of the intake conduit.
Pump flow testing apparatus have been devised, and one example is disclosed in U.S. Pat. No. 6,386,049 to Schrumm. The Schrumm pump flow test system employs a manifold assembly that needs to be anchored in place using the weight of a vehicle to counter the recoil or reaction force of the water leaving the manifold assembly. Also, rather than using a conventional foldable reservoir, the Schrumm system uses a specialized or modified reservoir structure in which a hole is formed in the side wall of the reservoir structure to accept a tube portion of the manifold assembly that carries the water flow from the pump. A seal thus needs to be formed and maintained between the tube and the hole in the side wall of the reservoir structure to prevent water leakage. Thus the Schrumm system may be vulnerable to leakage if the seal is not properly formed upon each set up of the system, and may especially become a problem after the system has been repeatedly set up and knocked down.
Further, the Schrumm system is designed to test the flow characteristics of the combined output of one or more of the pumps of a vehicle, or each of the pumps one at a time, but is not able to test more than one pump individually and simultaneously if desired. Thus, if more than one pump needs to be tested individually with the Schrumm system, the pumps have to be tested consecutively to get the desired individual results for the pumps.
Another concern is the need to test the pump or pumps of the fie fighting apparatus while avoiding taking the apparatus on which the pump is mounted out of service for long periods of time, since the pump may be mounted on the only fire fighting apparatus of its type possessed by the fire fighting entity and may unexpectedly be needed during the course of testing for fighting a fire.
Therefore, there is a need for a system that permits the use of relatively small reservoir sizes for permitting maximum portability and ease of set up and knock down, while minimizing any negative effects on pump performance by the use of the small reservoir.